Outside Trim Joints Opening Wide
DavidAndersen
| Posted in Construction Techniques on
1 week ago I installed my first round of exterior trim – poplar, primed on all sides. Window casings, water table, and drip edge (on top of the water table) are primarily what I installed. All the joints were tight, or nearly tight. After 1 week, my window casings (the legs) are no longer flush with the sills on the outside edges (1/16th over) and the outside corner miter joints for the drip edge have opened up to 1/4″ and slightly more. I note the inside (closest to the house) of these miter joints is still tight.
1. Why did this happen and how can I avoid it for the remaining trim?
2. What can I do to fix it?
Thanks.
Replies
Obviously you have had wood movement. If you used KD poplar, it will expand once placed outside. The primer will only mitigate a portion of the moisture, a top coat of paint will add more protection but not make up for the dry lumber.
To avoid this happening again, use different lumber. Poplar has a reputation for painting well. I ask, compared to what? It would not be one of my choices for exterior trim. The standard in my area is white pine, air dried. All wood will move. You can't make all your exterior trim stay perfect. There will be some boards that will move or warp.
The only thing you can do now is replace/reposition the offending pieces or use caulking and filler. Sorry, I'm sure you're upset after doing a nice job. If you have more of the same to install, I would let it aclimate and paint it before installing.
Beat it to fit / Paint it to match
I'm sure you did what you thought was right, and it sounds like you did a good job, but poplar is not a good exterior wood. Its got a very low resistance to rot. I've seen exterior poplar rotted out in 5 years or less.
The main problem seems to be that the poplar was too dry, and has opened up after being outside. I do like to glue any joint to help keep it together. I just bought a bottle of the new Titebond III to try out.
Please consider using a different wood, or one of the composite materials for your trim. Its discouraging to put time and effort into your work, just to end up with disappointing results.
wrong...sorry pal...my house has poplar from 175 yrs ago..it's not a bad thing, in fact, I will use more of it.
Any wood will degrade with time, and lack of loving..don't blanketly dismiss yellow Poplar as a bad thing.
Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations.
From what I understand, there are 2 species of wood commonly called poplar, depending on what area of the country you're from. I've had 2 jobs in the past year replacing poplar someone else installed. ( maybe thats a good thing?). Both were backprimed and painted well.
the stuff we get here in NJ is not a good exterior wood, and I wouldn't even consider using it with all the other options available.
I would also guess that wood on your house from 175 years ago is much different than what is available now.
On the old houses arond here, and I've worked on my share, the wood of choice seems to be pine, but even that old pine has a much tighter growth ring pattern than what is normally available nowadays.
I still think poplar is one of the best woods for interior trim, and I've used it in my own house, but my experience with poplar outside hasn't been good.
The joints were tight, now they are loose. I know wood moves, but I didn't expect it to move 1/4" in 1 week.
Wouldn't this indicate wood that has shrunk because it had more moisture content before being outside?
Wouldn't this indicate that it was not kiln dried to an appropriate level?
The wood has almost always been outside (in the unheated garage when bare, in a covered porch after priming), so I don't know why it would not have acclimated well enough.
The poplar was suggested by a local carpenter who uses it all the time on exteriors. He's well regarded and does excellent work, so I have no reason to think poplar is a bad choice.
If you kept the casings flush with the sill ears, and now they stick out 1/16" that would indicate the casings have swollen. When miters expand they open up. The short point of your cap is against the wall, as it expands the outside corner opens up. Inside corners are tight because the expansion pushes the joint tight.
Sphere is right about poplar not rotting anymore than other species. I made some saw horses out of it and they lasted over twenty years unfinished and contacting the ground. They would still be around if not for that truck. The problem with poplar is that it is a fast growing tree, wide growth rings, I think this makes it more susceptible to movement. It is a dry wood, not much sap or oils. Anytime I have used it for things that get exposed to weather, it swells. I made some carpenter tool chests that would occasionally get rained on. They were thoroughly finished but the tops and sides moved enough to push out at the long corners. If you wet a raw board, the grain really raises. It is also more expensive than other options for me.
Your poplar, at least, was not fresh from a warm shop. The primer alone won't stop the wood cells from doing their thing. A coat of paint will improve its moisture resistance and may be your best bet right now regardless if it's shrinking or swelling.
Beat it to fit / Paint it to match
Have a look at this article by Gary Katz and see if this helps.
http://www.garymkatz.com/TrimTechniques/OpenMiters.htm
Who Dares Wins.
Thanks. He explains the problem in this article, but promises the solution in a future one. I sent him a note.
David
I'm with the poplar being a bad exterior wood. Contrary to what sphear said. IF he is correct in his identification it should be noted that almost anything old growth is better than whats being cranked out today. That said I made a custom closet door for a client out of kd poplar and within a few months it had twisted a bit. The stuff is not that stable. You should use the ceaders or mahoganies (not philapine aka meranti) white oak is good for sills. And belive it or not, walnut is a very good wood for exterior use although its too pretty and expensive for that anymore. You should also look at the new synthetics like Azek (PVC based)
I wouldn't want to be around when finds out somebody questions his species id! The fir is gonna fly now when he lays the wood to ya. You'll be pine-ing for the time before you made that comment. his knowledge of species is as solid as Oak. He'll whup your ash with a hickory stick.
guess I'll go hide my self now in a cedar chest until this blows over, then come pick up the deadfall.
LOL
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Are you saying I made an aspen of myself. Maybe he could show us a pic of this 150yr old wood.
piffin,
I think there is going to be a lot of groaning from the elders on that post of yours. Gawd your awful, but that was very very good.
groan,
m2akita
I was trying to make a point, not to be poplar. If a tree were acting like a politician, it'd be a cottonwood, or a quaking aspen.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
LMAO...I just let it slide. I KNOW it's poplar, can't miss the signs. Contrary to belief not all pop. is fast grown nowadays, any that is competeing in dense canopy is as slow grown as the old stuff, the decay resistance is all about the heart wood vs. the sap wood.
All of my trim in and out was Yellow or Tulip pop. ALL of it was heartwood. Very dark green and brownish purple. Now to be honest some of the shingle trim IS punky, but that was subjected to a lot of weather over the yrs, and birds , squirrels, bees. I have it one good authority that that is the original trim, from before the metal roof installed in 1905.
Pop was used not because of the rot issue but because it was (A) plentiful, (B) not prized for furniture (C) easy to work
The logs here are White Oak, and chestnut...and for sill logs I would think locust woulda been used, but they chose Pop. Termites leave it aalone. The old school haouse I worked on last spring, all the under framing was pop, and still good, it was built in 1844.
Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations.
You used polar for exterior trim. is is a great trim wood for interior, but is not the most stable wood for exposure to moisture.
Welcome to the
Taunton University of Knowledge FHB Campus at Breaktime.
where ...
Excellence is its own reward!
Welcome to the rough framer's paradise.
Thank the holy heavens for painters that know how to caulk.
blue